RÉSUMÉ
OBJECTIVE@#To explore the expression and significance of second mitochondria derived activator of caspase (Smac), X-linked inhibitor of apoptosis protein (XIAP)and cysteine containing aspartate specific protease 3 (caspase-3) in the growth, development and carcinogenesis of the nonnasal inverted papilloma (NIP).@*METHOD@#Immunohistochemical method was used to detect the expression of Smac, XIAP, caspase-3 in 10 cases of nasal cavity mucosae (NM) and 45 cases of NIP, the group of NIP including 25 cases of NIP without dysplasia, 11 cases of NIP with dysplasia, and 9 cases of NIP with malignant transformation to squamous cell carcinoma (SCC).@*RESULT@#The intensity of the positive expression of Smac, Caspase-3 in NIP were lower than NM, the intensity of the positive expression decreased with the decreasing degree of histological differentiation. There was a significant difference between NIP without dysplasia and SCC. It was presented with a progressive tendency for the expression of XIAP in the group of NM and NIP. The lower degree of histological differentiation, the higher intensity of the positive expression. The expression between NIP without dysplasia and SCC had a significant difference. Smac negatively correlated with XIAP (r(s) = -0.323, P < 0.05), XIAP negatively correlated with caspase-3 (r(s) = -0.408, P < 0.01), Smac positively correlated with caspase 3 (r(s) = 0.424, P < 0.01).@*CONCLUSION@#Smac, XIAP, caspase 3 might be associated with the growth and carcinogenesis of NIP.